Euxesta leucomelas ( Walker, 1861 )

Korneyev, Severyn V., Hauser, Martin, Kameneva, Elena P. & Gaimari, Stephen D., 2022, A key to species of the Euxesta sororcula species group (Diptera: Ulidiidae: Lipsanini), with new synonymy and a new record from the U. S. A., The Pan-Pacific Entomologist 98 (2), pp. 150-162 : 154-155

Euxesta leucomelas ( Walker, 1861)

Fig. 1b

Ortalis leucomelas Walker, 1861:325 (description).

Euxesta leucomelas : Hendel, 1909:171 (key); 1910:27 (catalog, combination); Steyskal, 1968:54. 18 (catalog).

Euxesta fascipennis Wulp, 1899:398 (description); Hendel, 1910:26 (catalog); Curran, 1935:12 (key); Steyskal, 1968:54. 18 (catalog, synonymy).

Type specimens. Syntype, Ortalis leucomelas , [1 specimen, sex unknown], [Brazil] (BMNH(E)252334). Not examined .

Syntypes, Euxesta fascipennis , 7 ♂, 3 ♀ labeled: “Mexico, Orizaba” (H. H. Smith & F. D. Godman), “Tepetlapa in Guerrero 3000 feet, Medellin near Vera Cruz, Teapa in Tabasco (H. H. Smith)” (BMNH(E)252325–252333). Not examined.

Remarks. Walker (1861) described O. leucomelas based on an unknown number of specimens of unknown sex as follows:

“ Nigro-viridis, antennis pedibus que nigris, tarsis piceis, alis albis nigro-quadrifasciatis, fascia 1â basali, 2â 3â que posticèdilatatis, 4â costali; halteribus albis.

Blackish-green; antennae and legs black; tarsi piceous; wings white, with four black bands; first band near the base; second broad, much dilated hindward; third narrow, also dilated hind- ward; fourth costal, joining the third at much beyond half the length of the costa, and extending thence to a little beyond the tip of the wing; discal transverse vein parted by one-fourth of its length from the border, and by more than twice its length from the praebrachial transverse vein; halteres white. Length of the body 2 ½ lines; of the wings 4 lines. South America.”

Wulp (1899) described his species (as E. fascipennis ) as follows, and provided the figure reproduced here ( Fig. 1b ):

“Metallic bluish-black; frons and antennae rufous; legs blackish; wings hyaline, with four blackish bands, the discal and subapical much enlarged towards the hind margin, the fourth at the tip of the wing and narrower than the hyaline space before it.

Length 3. 5 mm.

Closely related to E. latifasciata and agreeing with it in most of its characters. The metallic coloration is more obscure, but on the face it is more extended; the tip of the scutellum is not rufous; the abdomen is more shining black; the legs are blackish, the femora with metallic green reflections, the base only of the tarsi rufous (in one of the specimens, perhaps a not fully coloured one, the legs are rufous). The discal and subapical bands on the wings, though enlarged towards the hind margin, are narrower than in E. latifasciata , and the hyaline space between the subapical and apical ones is much broader than the bands themselves. The apical joint of the ovipositor of the female is cylindrical and rufous.”

Both nominal species were considered synonyms by Steyskal (1968) in his Neotropical Catalogue based on the study of the types from the NHMUK, but without designation of lectotypes. Walker (1861) did not state the number or sex of his type specimens, so the single specimen in the Saunders collection labeled as this species formally has the status of syntype.

The Data Portal of the NHMUK ( BMNH 2021a, b, c) refers to “holotype” and “lectotype and paralectotypes” of both nominal species, but they are all actually syntypes.

Distribution. Brazil, Guyana, Mexico.

Figures

Figure 1. Wings: (a) Euxesta latifasciata; (b) E. leucomelas (=E. fascipennis); (c) E. wettsteini; (d) E. abdominalis, syntype, MCZ; (e) E. sororcula, type, NHMD; (f) E. obliquestriata, syntype, NHMW. (a–b modified from Wulp (1899); and d modified from EOL site https://eol. org/pages/734579/media). Abbreviations: SA = subapical band; A = apical band; phi – preapical hyaline interspace. Fine black lines show the ratio of SA and phi along vein R4+5 and light blue arrows indicate other characters mentioned in the key.